Drill rod with dust-collecting means

ABSTRACT

A drill rod for use in rotary percussion drilling includes an elongated inner solid core member and an outer tubular member positioned coaxially around the inner core member. The outer tubular member is spaced from the core member to provide a passageway therebetween for the flow of dust and drill cuttings therethrough. The outer tubular member has a plurality of longitudinal ports adjacent the bit through which the dust and cuttings enter the passageway. The bit is supported by the inner core member in a recessed axial bit-shank-receiving portion and the percussive and torsional forces are transmitted to the drill bit through the inner core member.

ited States Patent Primary Examiner David H. Brown Attorney-Stanley J. Price, Jr,

ABSTRACT: A drill rod for use in rotary percussion drilling includes an elongated inner solid core member and an outer tubular member positioned coaxially around the inner core member. The outer tubular member is spaced from the core member to provide a passageway therebetween for the flow of dust and drill cuttings therethrough. The outer tubular member has a plurality of longitudinal ports adjacent the bit through which the dust and cuttings enter the passageway. The bit is supported by the inner core member in a recessed axial bit-shank-receiving portion and the percussive and torsional forces are transmitted to the drill bit through the inner core member.

' PATENTEUnm 19 I97! INVENTOI? ALEX J. GAL/.5

M Q his Attorney DRILL ROD WITH DUST-COLLECTING MEANS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a drill rod having a dust withdrawal passageway therein and more particularly a drill rod having a solid core portion and an outer tubular member.

2. Description of the Prior Art In underground mining operations the mine roof is conventionally supported by roof bolts that include an expansible shell end portion and a bearing plate other end portion. Vertical boltholes are drilled in the mine roof by drilling machines. Bolts are positioned in the boltholes and rotated to expand the shell into engagement with the wall of the hole and urge the bearing plate upwardly against the roof surface to thereby compress the rock strata therebetween. Recently the speed at which the boltholes are drilled has increased substantially by imparting both rotary and percussive forces to the drill bit although in certain strata rotary or percussive forces are most effective. During the drilling operation a substantial amount of dust is created and dust-collecting means are a necessity to reduce the hazards created.

In rotary percussion drilling the drill rod is subjected to longitudinal percussive forces and rotary torque during the drilling operation. Because of V the dust created during the drilling operation, the drill rods include axial withdrawal passageways. The prior art drill rods are of a one-piece tubular design fabricated from heat-treated steel. Longitudinal dust ports are provided adjacent the drill bit any by means of suction the dust and cuttings are channeled through the dust ports into the inner longitudinal passageway of the tubular drill rod.

SUMMARY OF THE INVENTION Briefly, the invention is directed to a drill rod that includes a solid core member with a relatively thin tubular outer member positioned therearound. The core member and tubular outer member are so dimensioned that a longitudinal dust passageway is provided therebetween. The drill bit is secured to the core member and both the rotary and percussive forces are transmitted through the solid core member to the drill bit. Elongated dust ports are provided in the outer tubular member adjacent the drill bit for the flow of dust from the drill bit into the longitudinal dust passageway between the inner and outer members. With the conventional one-piece tubular design, the percussive forces exerted on the drillrod soon flare the end portion of the drill rod adjacent the drill bit so that replacement is necessary. Further, the tubular design limits the amount of percussive force and rotary torque that can be applied to the drill bit through the drill rod.

Accordingly, the principal object of this invention is to provide a drill rod having a solid core member and a tubular outer member positioned coaxially thereon.

Another object of this invention is to provide a drill rod that may be subjected to substantial percussive forces without outward flaring of the drill rod end portion.

These and other objects and advantages of this invention will be more completely disclosed and described in the following specification, the accompanying drawings and the ap pended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary view in elevation and partially in section of my improved drill rod illustrating a bit connected to the inner core member.

FIG. 2 is a view in section taken along the line 2-2 of FIG. 1.

FIGS. 3, 4, 5 and 6 are views similar to FIG. 2 and illustrating other configurations of the inner core member.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring particularly to FIGS. 1 and 2, there is illustrated a drill rod generally designated by the numeral 10 that includes an inner core member 12 and an outer tubular member 14. The inner core member 12 has a generally rectangular cross section with sidewalls 16, 18, 20, and 22. The inner core member 12 is preferably fabricated from a solid metal bar and may have difi'erent lengths depending upon the height of the entry or passageway in which it is used.

The inner core member 12 has an upper end portion 24 with an axial hexagonal recessed portion 26 arranged to receive a mating hexagonally shaped drill bit stem portion 28 of a drill bit generally designated by the numeral 29. The recessed portion 26 is so dimensioned that the head portion 30 of drill bit 29 abuts the inner core member upper end surface 24. A transverse passageway 32 extends through the inner core member and mates with a passageway 34 in the bit stem portion 28. A pin member 36 secures the bit stem 28 in the core member recessed portion 26 so that the drill bit 29 is rotated by the core member 12. Where the drill rod 12 is employed in a rotary percussive drill, the longitudinal percussive forces are transmitted through the inner core member 12 to the drill bit 29.

The tubular outer member 14 is coaxially positioned around the inner core member 12 and preferably has a cylindrical configuration as illustrated. The external diameter of the outer tubular member 14 is less than the major transverse dimension of the drill bit 29 to provide a slight clearance between the hole drilled by the drill bit 29 and the outer tubular member 14. The outer tubular member 14 may be fabricated from any suitable material such as thin-walled metal tubing or from relatively rigid plastic material. The function of the outer tubular member 14 is solely to provide an outer wall for the flow passageway to convey the cuttings created during the drilling operation. The tubular member 14 does not transmit either percussive or torsional forces to the drill bit 29. All of the percussive and torsional forces are transmitted by the inner core member 12.

The outer tubular member 14 has a plurality of longitudinally extending dust ports 38 through which the cuttings and dust created by the bit 29 during the drilling operation enter the internal passageway 40 formed between the outer tubular member inner cylindrical wall 42 and the outer walls 16, 18, 20 and 22 of the inner core member 12. The outer tubular member upper annular end portion 41 is illustrated in FIG. 1 as spaced from the underside 43 of drill bit head portion 30. This arrangement provides an annular port 45 for the flow of dust and cuttings into the passageway 40. Where desired, depending on the suction in passageway 40, the upper annular edge portion may be positioned in abutting relation with the drill bit head under side 43 thus eliminating the annular port 45 so that the longitudinal ports 38 are the only ports opening into the passageway 40. For other uses the longitudinal ports 38 may be omitted so that the annular port 45 is the only port opening into the passageway 40.

The lower portion of the tubular member 14 is connected to a suction pump in a similar manner as conventional drill rods are connected to a suction as illustrated in U.S. Pat. No. 3,144,912 and No. 3,022,840. The outer tubular member 14 should have sufficient rigidity when the passageway 40 is connected to a suction pump that it maintains its tubular configuration and does not collapse under the negative suction pressure.

With this arrangement the inner core member 12 transmits both the percussive and torsional forces from the drill head (not shown) to the drill bit 29. Suction is imparted to the passageway 40 between the inner core member 12 and the outer tubular member 14 so that cuttings and dust formed during the drilling operation flow through the ports 38 and 45 into the passageway 40 and through the elongated passageway 40 to a suitable dust-collecting means. Because of its solid configuration, the core member 12 is operable to transmit substantial percussive and torsional forces to the drill bit without damaging either the inner core member 12 or the outer tubular member 14. Suitable spacing devices may be provided to maintain the outer tubular member 14 in spaced relation to the inner core member 12. The outer tubular member 14 may be suitably connected to the inner core member 12 to rotate therewith or may be fixedly connected to the drill head so that the inner core member 12 rotates relative thereto.

Referring to FIG. 3 where similar numerals designate similar parts, there is illustrated another embodiment of the inner core member 12 where the core member 12 has a generally rectangular configuration in section as compared with the generally square configuration of the core member illustrated in FIG. 2. The passageway 40 has substantially the same cross-sectional area as that illustrated in FIG. 2. Where desired, the transverse dimension of the core member 12 may be such that corners of the core member 12 abut the outer member inner cylindrical wall 42 thus forming four separate dust flow passages between the inner cylindrical wall 42 and the outer walls 16, 18, 20 and 22 of core member 12.

FIG. 4 is an illustration of another configuration of the inner core member 12 where the core member has a hexagonal shape in section with walls 44, 46, 48, 50, 52 and 54. The outer tubular member 14 has separate dust ports 38 opposite each of the walls 44 for the flow of dust between the inner cylindrical wall 42 and the walls 44, 46, 48, 50, and 54 of the core member 12.

FIG. illustrates another configuration of the inner core member 12 that is preferably formed as an extrusion and has walls 55, 56, 58 and 60 with radially extending ribs 62, 64, 66 and 68 at the intersection of the walls. The radially extending ribs provide suitable means for maintaining the outer tubular member 14 axially aligned with the inner core member 12 while maintaining dust flow passageways 40 therebetween.

FIG. 6 illustrates a core member 12 having a generally cylindrical configuration with an outer cylindrical wall 70. Suitable spacer devices such as screws 72 and 74 may be provided in the outer tubular member 14 to maintain the outer tubular member 14 coaxially aligned with the inner core member 12.

The core member 12 may be formed from inexpensive bar stock and the outer tubular member may be formed from inexpensive lightweight metal or plastic tubing. The percussive and torsional forces are transmitted from the drill head to the drill bit through the inner core member 12 while the outer tubular member 14 functions primarily as a means to provide a dust flow passageway. The above-described drill rod eliminates the requirement for tough heat-treated seamless steel tubular drill rods and eliminates the damage to the end of the drill rods incurred by the transmission of percussive forces therethrough. It should be understood that the core member 12 may have any suitable configuration in section. The core member 12 is preferably solid and the configuration is controlled only by the provision of dust flow passageways between the outer surface of the core member 12 and the inner surface of the outer tubular member 14. It should also be understood that the outer member 14 need not be restricted to the cylindrical shape illustrated in the drawings. The outer member 14 may have other configurations as long as dust flow passages are provided between the inner core member and the coaxial outer core member.

According to the provisions of the patent statutes, I have explained the principle, preferred construction and mode of operation of my invention and have illustrated and described what I now consider to represent its best embodiments.

I claim:

1. A drill rod for a rotary percussive drill comprising,

an elongated inner core member having a drill-bit-receiving end portion and sidewalls, an elongated outer tubular member having an axial opening therethrough with an inner wall, an outer wall and anannular end portion, I said inner core member positioned coaxially within said outer tubular member in spaced relation thereto to provide a passageway between said inner core member sidewalls and said outer tubular member inner wall,

said outer tubular member having elongated longitudinally extending ports therethrough adjacent said annular end portion and forming inlet means to said passageway adjacent said core member drill-bit-receiving end portion for the entry of dust and cuttings created by a drill bit during the drilling operation, and

said inner core member having suflicient rigidity to transmit both rotational and percussive forces to a drill bit adapted to be secured in said core member drill-bit-receiving end portion.

2. A drill rod as set forth in claim 1 in which,

said inner core member has a generally solid rectangular configuration in section, and

said outer tubular member has a generally cylindrical shape in section and is formed relatively thin-walled tubing sufficient to maintain the cylindrical configuration when a suction is imparted to said passageway during the drilling operation.

3. A drill rod as set forth in claim 1 in which, said outer tubular member annular end portion is spaced from the head portion of a drill bit providing an annular opening that forms another inlet means to said passageway.

4. A drill rod as set forth in claim 1 in which,

said inner core member has an axial bit-receiving recess in said bit-receiving end portion operable to receive and secure the shank portion of a drill bit therein so that both rotation and percussion are transmitted through said inner core member to the drill bit.

5. A drill rod as set forth in claim 1 in which,

said inner core member has a generally solid cylindrical configuration,

said outer tubular member has a generally cylindrical configuration, and

means secured to said outer tubular member and abutting said inner core member to maintain an annular passageway therebetween.

6. A drill rod as set forth in claim 1 in which,

said inner core member is metal and said outer tubular member is plastic. 

1. A drill rod for a rotary percussive drill comprising, an elongated inner core member having a drill-bit-receiving end portion and sidewalls, an elongated outer tubular member having an axial opening therethrough with an inner wall, an outer wall and an annular end portion, said inner core member positioned coaxially within said outer tubular member in spaced relation thereto to provide a passageway between said inner core member sidewalls and said outer tubular member inner wall, said outer tubular member having elongated longitudinally extending ports therethrough adjacent said annular end portion and forming inlet means to said passageway adjacent said core member drill-bit-receiving end portion for the entry of dust and cuttings created by a drill bit during the drilling operation, and said inner core member having sufficient rigidity to transmit both rotational and percussive forces to a drill bit adapted to be secured in said core member drill-bit-receiving end portion.
 2. A drill rod as set forth in claim 1 in which, said inner core member has a generally solid rectangular configuration in section, and said outer tubular member has a generally cylindrical shape in section and is formed relatively thin-walled tubing sufficient to maintain the cylindrical configuration when a suction is imparted to said passageway during the drilling operation.
 3. A drill rod as set forth in claim 1 in which, said outer tubular member annular end portion is spaced from the head portion of a drill bit providing an annular opening that forms another inlet means to said passageway.
 4. A drill rod as set forth in claim 1 in which, said inner core member has an axial bit-receiving recess in said bit-receiving end portion operable to receive and secure the shank portion of a drill bit therein so that both rotation and percussion are transmitted through said inner core member to the drill bit.
 5. A drill rod as set forth in claim 1 in which, said inner core member has a generally solid cylindrical configuration, said outer tubular member has a generally cylindrical configuration, and means secured to said outer tubular member and abutting said inner core member to maintain an annular passageway therebetween.
 6. A drill rod as set forth in claim 1 in which, said inner core member is metal and said outer tubular member is plastic. 